ECRIT R. Gellens
Internet-Draft Qualcomm Technologies, Inc.
Intended status: Standards Track B. Rosen
Expires: January 20, 2016 NeuStar
H. Tschofenig
R. Marshall
TeleCommunication Systems, Inc.
J. Winterbottom
July 19, 2015
Additional Data Related to an Emergency Calldraft-ietf-ecrit-additional-data-33.txt
Abstract
When an emergency call is sent to a Public Safety Answering Point
(PSAP), the originating device, the access network provider to which
the device is connected, and all service providers in the path of the
call have information about the call, the caller or the location
which is helpful for the PSAP to have in handling the emergency.
This document describes data structures and mechanisms to convey such
data to the PSAP. The intent is that every emergency call carry the
information described here using the mechanisms described here.
The mechanisms permit the data to be conveyed by reference (as an
external resource) or by value (within the body of a SIP message or a
location object). This follows the tradition of prior emergency
services standardization work where data can be conveyed by value
within the call signaling (i.e., in the body of the SIP message) or
by reference.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This document defines three categories of this additional data that
can be transmitted with an emergency call:
Data Associated with a Location: Primary location data is conveyed
in the Presence Information Data Format Location Object (PIDF-LO)
data structure as defined in RFC 4119 [RFC4119] and extended by
RFC 5139 [RFC5139] and RFC 6848 [RFC6848] (for civic location
information), RFC 5491 [RFC5491] and RFC 5962 [RFC5962] (for
geodetic location information), and [RFC7035] (for relative
location). This primary location data identifies the location or
estimated location of the caller. However, there may exist
additional, secondary data which is specific to the location, such
as floor plans, tenant and building owner contact data, heating,
ventilation and air conditioning (HVAC) status, etc. Such
secondary location data is not included in the location data
structure but can be transmitted using the mechanisms defined in
this document. Although this document does not define any
structures for such data, future documents may do so following the
procedures defined here.
Data Associated with a Call: While some information is carried in
the call setup procedure itself (as part of the SIP headers as
well as in the body of the SIP message), there is additional data
known by the device making the call, the access network to which
the device is connected, and service providers along the path of
the call. This information includes service provider contact
information, subscriber identity and contact information, the type
of service the service provider and the access network provide,
what type of device is being used, etc. Some data is broadly
applicable, while other data is dependent on the type of device or
service. For example, a medical monitoring device may have sensor
data. The data structures defined in this document (Data Provider
Information, Device Information, and Owner/Subscriber Information)
all fall into the category of "Data Associated with a Call". Note
that the Owner/Subscriber Information includes the subscriber's
vCard, which may contain personal information such as birthday,
anniversary, etc., but the data block itself is still considered
to be about the call, not the caller.
Data Associated with a Caller: This is personal data about a caller,
such as medical information and emergency contact data. Although
this document does not define any structures within this category,
future documents may do so following the procedures defined here.
While this document defines data structures only within the category
of Data Associated with a Call, by establishing the overall framework
of Additional Data, along with general mechanisms for transport of
such data, extension points and procedures for future extensions, it
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minimizes the work needed to carry data in the other categories.
Other specifications may make use of the facilities provided here.
For interoperability, there needs to be a common way for the
information conveyed to a PSAP to be encoded and identified.
Identification allows emergency services authorities to know during
call processing which types of data are present and to determine if
they wish to access it. A common encoding allows the data to be
successfully accessed.
This document defines an extensible set of data structures, and
mechanisms to transmit this data either by value or by reference,
either in the Session Initiation Protocol (SIP) call signaling or in
the Presence Information Data Format Location Object (PIDF-LO). The
data structures are usable by other communication systems and
transports as well. The data structures are defined in Section 4,
and the transport mechanisms (using SIP and HTTPS) are defined in
Section 5.
Each data structure described in this document is encoded as a
"block" of information. Each block is an XML structure with an
associated Multipurpose Internet Mail Extensions (MIME) type for
identification within transport such as SIP and HTTPS. The set of
blocks is extensible. Registries are defined to identify the block
types that may be used and to allow blocks to be included in
emergency call signaling.
Much of the information supplied by service providers and devices is
private and confidential; service providers and devices generally go
to lengths to protect this information; disclosing it in the context
of an emergency call is a trade-off to protect the greater interest
of the customer in an emergency.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
This document also uses terminology from [RFC5012]. We use the term
service provider to refer to an Application Service Provider (ASP).
A Voice Service Provider (VSP) is a special type of ASP. With the
term "Access Network Provider" we refer to the Internet Access
Provider (IAP) and the Internet Service Provider (ISP) without
further distinguishing these two entities, since the difference
between the two is not relevant for this document. Note that the
roles of ASP and access network provider may be provided by a single
company. An Emergency Services Provider is an entity directly
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involved in providing emergency services. This includes PSAPs,
dispatch, police, fire, emergency medical, other responders, and
other similar agencies.
Within each data block definition (see Section 4), the values for the
"Use:" label are specified as one of the following:
'Required': means it MUST be present in the data structure.
'Conditional': means it MUST be present if the specified
condition(s) is met. It MAY be present if the condition(s) is not
met.
'Optional': means it MAY be present.
vCard [RFC6350] is a data format for representing and exchanging a
variety of information about individuals and other entities. For
applications that use XML, the format defined in vCard is not
immediately applicable. For this reason, an XML-based encoding of
the information elements defined in the vCard specification has been
defined and the name of that specification is xCard [RFC6351]. Since
the term vCard is more familiar to most readers, we use the terms
xCard and vCard interchangeably.
3. Document Scope
The scope of this document is explicitly limited to emergency calls.
The data structures defined here are not appropriate to be conveyed
with non-emergency calls because they carry sensitive and private
data. However, in certain private-use situations where the endpoints
have a preexisting relationship and privacy issues are addressed
within the relationship or do not apply because of it, the mechanisms
and data structures defined here MAY be used.
4. Data Structures
This section defines the following five data structures, each as a
data block. For each block we define the MIME type, and the XML
encoding. The five data structures are:
'Data Provider': This block supplies name and contact information
for the entity that created the data. Section 4.1 provides the
details.
'Service Information': This block supplies information about the
service. The description can be found in Section 4.2.
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'Device Information': This block supplies information about the
device placing the call. Device information can be found in
Section 4.3.
'Owner/Subscriber': This block supplies information about the owner
of the device or about the subscriber. Details can be found in
Section 4.4.
'Comment': This block provides a way to supply free form human
readable text to the PSAP or emergency responders. This simple
structure is defined in Section 4.5.
Each block contains a mandatory <DataProviderReference> element. The
purpose of the <DataProviderReference> element is to associate all
blocks added by the same data provider as a unit. The
<DataProviderReference> element associates the data provider block to
each of the other blocks added as a unit. Consequently, when a data
provider adds additional data to an emergency call (such as device
information) it MUST add information about itself (via the data
provider block) and the blocks added contain the same value in the
<DataProviderReference> element. All blocks added by a single entity
at the same time MUST have the same <DataProviderReference> value.
The value of the <DataProviderReference> element has the same syntax
and properties (specifically, world-uniqueness) as the value of the
"Message-ID" message body header field specified in RFC 5322
[RFC5322] except that the <DataProviderReference> element is not
enclosed in brackets (the "<" and ">" symbols are omitted). In other
words, the value of a <DataProviderReference> element is
syntactically a msg-id as specified in RFC 5322 [RFC5322].
Each block is added to the Additional Data Blocks Registry created in
Section 10.1.9 and categorized as providing data about the caller.
New blocks added to the registry in the future MUST also be
categorized per the description of the three categories in Section 1.
See Section 4.3.7 and Section 4.3.8 for additional considerations
when adding new blocks or types of data.
Note that the xCard format is re-used in some of the data structures
to provide contact information. In an xCard there is no way to
specify a "main" telephone number. These numbers are useful to
emergency responders who are called to a large enterprise. This
document adds a new property value to the "tel" property of the TYPE
parameter called "main". It can be used in any xCard in additional
data.
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This block is intended to be supplied by any service provider in the
path of the call, or the access network provider, and the device. It
includes identification and contact information. This block MUST be
supplied by any entity that provides any other block; it SHOULD be
supplied by every service provider in the call path and by the access
network provider if those entities do not add any other blocks.
Devices SHOULD use this block to provide identifying information.
The MIME subtype is "application/EmergencyCallData.ProviderInfo+xml".
An access network provider SHOULD provide this block either by value
or by reference in the <provided-by> element of a PIDF-LO
4.1.1. Data Provider String
Data Element: Data Provider String
Use: Conditional. Optional for blocks supplied by the originating
device, mandatory otherwise.
XML Element: <DataProviderString>
Description: This is a plain text string suitable for displaying the
name of the service provider that supplied the data structure. If
the device creates the structure, it SHOULD use the value of the
contact header in the SIP INVITE.
Reason for Need: Inform the call taker of the identity of the entity
providing the data.
How Used by Call Taker: Allows the call taker to interpret the data
in this structure. The source of the information often influences
how the information is used, believed or verified.
4.1.2. Data Provider ID
Data Element: Data Provider ID
Use: Conditional. Optional for blocks supplied by the originating
device, mandatory otherwise. This data MUST be provided by all
entities other than the originating device in order to uniquely
identify the service provider or access provider.
XML Element: <ProviderID>
Description: A jurisdiction-specific code for, or the fully-
qualified domain name of, the access network provider or service
provider shown in the <DataProvidedBy> element that created the
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structure. NOTE: The value SHOULD be assigned by an organization
appropriate for the jurisdiction. In the U.S., if the provider is
registered with NENA, the provider's NENA Company ID MUST appear
here. Additional information can be found at NENA Company
Identifier Program [1] or NENA Company ID [2]. The NENA Company
ID MUST be in the form of a URI in the following format:
urn:nena:companyid:<NENA Company ID>. If the organization does
not have an identifier registered with a jurisdiction-specific
emergency services registrar (such as NENA), then the value MAY be
the fully-qualified domain name of the service provider or access
provider. The device MAY use its IP address or fully-qualified
domain name (and set the "Data Provider ID Series" element to
"domain").
Reason for Need: Inform the call taker of the identity of the entity
providing the data.
How Used by Call Taker: Where jurisdictions have lists of providers
the Data Provider ID provides useful information about the data
source. The Data Provider ID uniquely identifies the source of
the data, which might be needed especially during unusual
circumstances and for routine logging.
4.1.3. Data Provider ID Series
Data Element: Data Provider ID Series
Use: Conditional. Optional for blocks supplied by the originating
device, mandatory otherwise.
XML Element: <ProviderIDSeries>
Description: Identifies the issuer of the <ProviderID>. The
Provider ID Series Registry created in Section 10.1.1 initially
contains the entries shown in Figure 1.
Reason for Need: Identifies how to interpret the Data Provider ID.
The combination of ProviderIDSeries and ProviderID MUST be
globally unique.
How Used by Call Taker: Determines which provider ID registry to
consult for more information
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+------------------------------+------------------------------------+
| Token | Description |
+------------------------------+------------------------------------+
|Client | Originating client/device |
|Access Network Provider | Access network service provider |
|Telecom Provider | Telecom service provider (including|
| | over-the-top VoIP services) |
|Telematics Provider | A sensor-based service provider, |
| | especially vehicle-based |
|Language Translation Provider | A spoken language translation |
| | service |
|Emergency Service Provider | An emergency service provider |
| | conveying information to another|
| | emergency service provider. |
|Emergency Modality Translation| An emergency-call-specific |
| | modality translation service |
| | e.g., for sign language |
|Relay Provider | A interpretation service, e.g., |
| | video relay for sign language |
| | interpreting |
|Other | Any other type of service provider |
+------------------------------+------------------------------------+
Figure 2: Type of Data Provider Registry
4.1.5. Data Provider Contact URI
Data Element: Data Provider Contact URI
Use: Required
XML Element: <ContactURI>
Description: When provided by a service provider or an access
network provider, this information MUST be a URI to a 24/7 support
organization tasked to provide PSAP support for this emergency
call. When provided by a device, this MUST be the contact
information of the user or owner of the device. (Ideally, this is
the contact information of the device user, but when the owner and
user are separate (e.g., the device owner is an organization),
this MAY be the contact information of the owner.) The Data
Provider Contact URI SHOULD be a TEL URI [RFC3966] in E.164 format
fully specified with country code. If a TEL URI is not available,
it MAY be a generic SIP URI. Note that this contact information
is not used by PSAPs for callbacks (a call from a PSAP directly
related to a recently terminated emergency call, placed by the
PSAP using a SIP Priority header field set to "psap-callback", as
described in [RFC7090]).
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Reason for Need: Additional data providers may need to be contacted
in error cases or other unusual circumstances.
How Used by Call Taker: To contact the supplier of the additional
data for assistance in handling the call.
4.1.6. Data Provider Languages(s) Supported
Data Element: Data Provider Language(s) supported
Use: Required.
XML Element: <Language>
Description: This field encodes the language used by the entity at
the Data Provider Contact URI. The content of this field consists
of a single token from the language tags registry, which can be
found at [LanguageTagRegistry], and is defined in [RFC5646].
Multiple instances of this element may occur but the order is
significant and the preferred language should appear first. The
content MUST reflect the languages supported at the contact URI.
(Note that this field informs the PSAP of the language(s) used by
the data provider. If the PSAP needs to contact the data
provider, it can be helpful to know in advance the language(s)
used by the data provider. If the PSAP uses a communication
protocol to reach the data provider, that protocol may have
language facilities of its own (such as the 'language' media
feature tag, defined in RFC 3840 [RFC3840] and the more extensive
language negotiation mechanism proposed with
[I-D.gellens-slim-negotiating-human-language]), and if so, those
are independent of this field.)
Reason for Need: This information indicates if the emergency service
authority can directly communicate with the service provider or if
an interpreter will be needed.
How Used by Call Taker: If the call taker cannot speak any language
supported by the service provider, a translation service will need
to be added to the conversation. Alternatively, other persons at
the PSAP, besides the call taker, might be consulted for help
(depending on the urgency and the type of interaction).
4.1.7. xCard of Data Provider
Data Element: xCard of Data Provider
Use: Optional
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XML Element: <DataProviderContact>
Description: Per [RFC6351] the xCard structure is represented within
a <vcard> element. Although multiple <vcard> elements may be
contained in a structure only one <vcard> element SHOULD be
provided. If more than one appears, the first SHOULD be used.
There are many fields in the xCard and the creator of the data
structure is encouraged to provide all available information. N,
ORG, ADR, TEL, EMAIL are suggested at a minimum. N SHOULD contain
the name of the support group or device owner as appropriate. If
more than one TEL property is provided, a parameter from the vCard
Property Value registry MUST be specified for each TEL. For
encoding of the vCard this specification uses the XML-based
encoding specified in [RFC6351], referred to in this document as
"xCard".
Reason for Need: Information needed to determine additional contact
information.
How Used by Call Taker: Assists the call taker by providing
additional contact information aside from what may be included in
the SIP INVITE or the PIDF-LO.
4.1.8. Subcontractor Principal
When the entity providing the data is a subcontractor, the Data
Provider Type is set to that of the primary service provider and this
entry is supplied to provide information regarding the subcontracting
entity.
Data Element: Subcontractor Principal
Use: Conditional. This data is required if the entity providing the
data is a subcontractor.
XML Element: <SubcontractorPrincipal>
Description: Some providers outsource their obligations to handle
aspects of emergency services to specialized providers. If the
data provider is a subcontractor to another provider this element
contains the DataProviderString of the service provider to
indicate which provider the subcontractor is working for.
Reason for Need: Identify the entity the subcontractor works for.
How Used by Call Taker: Allows the call taker to understand what the
relationship between data providers and the service providers in
the path of the call are.
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Data Element: Subcontractor Priority
Use: Conditional. This data is required if the entity providing the
data is a subcontractor.
XML Element: <SubcontractorPriority>
Description: If the subcontractor is supposed to be contacted first
then this element MUST have the value "sub". If the provider the
subcontractor is working for is supposed to be contacted first
then this element MUST have the value "main".
Reason for Need: Inform the call taker whom to contact first, if
support is needed.
How Used by Call Taker: To decide which entity to contact first if
assistance is needed.
4.1.10. ProviderInfo Example
<?xml version="1.0" encoding="UTF-8"?>
<ad:EmergencyCallData.ProviderInfo
xmlns:ad="urn:ietf:params:xml:ns:EmergencyCallData:ProviderInfo">
<ad:DataProviderReference>string0987654321@example.org
</ad:DataProviderReference>
<ad:DataProviderString>Example VoIP Provider
</ad:DataProviderString>
<ad:ProviderID>urn:nena:companyid:ID123</ad:ProviderID>
<ad:ProviderIDSeries>NENA</ad:ProviderIDSeries>
<ad:TypeOfProvider>Telecom Provider</ad:TypeOfProvider>
<ad:ContactURI>tel:+1-201-555-0123</ad:ContactURI>
<ad:Language>en</ad:Language>
<ad:DataProviderContact
xmlns="urn:ietf:params:xml:ns:vcard-4.0">
<vcard>
<fn><text>Hannes Tschofenig</text></fn>
<n>
<surname>Hannes</surname>
<given>Tschofenig</given>
<additional/>
<prefix/>
<suffix>Dipl. Ing.</suffix>
</n>
<bday><date>--0203</date></bday>
<anniversary>
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<geo>
<parameters><type><text>work</text></type>
</parameters>
<uri>geo:60.210796,24.812924</uri>
</geo>
<key>
<parameters><type><text>home</text></type>
</parameters>
<uri>
http://www.tschofenig.priv.at/key.asc
</uri>
</key>
<tz><text>Finland/Helsinki</text></tz>
<url>
<parameters><type><text>home</text></type>
</parameters>
<uri>http://www.tschofenig.priv.at</uri>
</url>
</vcard>
</ad:DataProviderContact>
</ad:EmergencyCallData.ProviderInfo>
Figure 3: EmergencyCallData.ProviderInfo Example.
4.2. Service Information
This block describes the service that the service provider provides
to the caller. It SHOULD be included by all service providers in the
path of the call. The mime subtype is "application/
EmergencyCallData.ServiceInfo+xml".
4.2.1. Service Environment
Data Element: Service Environment
Use: Conditional: Required unless the 'ServiceType' value is
'wireless'.
XML Element: <ServiceEnvironment>
Description: This element indicates whether a call is from a
business or residence. Currently, the only valid entries are
'Business', 'Residence', and 'unknown', as shown in Figure 4. New
values can be defined via the registry created in Section 10.1.2.
Reason for Need: To provide context and a hint when determining
equipment and manpower requirements.
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How Used by Call Taker: Information may be used to provide context
and a hint to assist in determining equipment and manpower
requirements for emergency responders. Because there are
situations where the service provider does not know (such as
anonymous pre-paid service), and because the type of service does
not neccessarily reflect the nature of the premises (for example,
a business line installed in a residence, or wireless service),
and the registry is not all-encompassing, this is at best advisory
information, but since it mimics a similar capability in some
current emergency calling systems (e.g., a field in the Automatic
Location Information (ALI) information used with legacy North
American wireline systems), it is known to be valuable. The
service provider uses its best information (such as a rate plan,
facilities used to deliver service or service description) to
determine the information and is not responsible for determining
the actual characteristics of the location from which the call
originated. Because the usefulness is unknown (and less clear)
for wireless, this element is OPTIONAL for wireless and REQUIRED
otherwise.
+-----------+--------------------------+
| Token | Description |
+-----------+--------------------------+
| Business | Business service |
| Residence | Residential service |
| unknown | Type of service unknown |
| | (e.g., anonymous pre- |
| | paid service) |
+-----------+--------------------------+
Figure 4: Service Environment Registry
4.2.2. Service Type
Data Element: Service Delivered by Provider to End User
Use: Required
XML Element: <ServiceType>
Description: This defines the type of service over which the call is
placed (similar to the Class of Service delivered with legacy
emergency calls in some some regions). The implied mobility of
this service cannot be relied upon. A registry is created in
Section 10.1.3. The initial set of values is shown in Figure 5.
More than one value MAY be returned. For example, a VoIP inmate
telephone service is a reasonable combination.
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Reason for Need: Knowing the type of service may assist the PSAP in
handling of the call.
How Used by Call Taker: Call takers often use this information to
determine what kinds of questions to ask callers, and how much to
rely on supportive information. An emergency call from a prison
is treated differently than a call from a sensor device. As the
information is not always available, and the registry is not all-
encompassing, this is at best advisory information, but since it
mimics a similar capability in some legacy emergency calling
systems, it is known to be valuable.
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Description: This provides the service provider's view of the
mobility of the caller's device. As the service provider might
not know the characteristics of the actual device or access
network used, the value should be treated as advisory and not be
relied upon. A registry is created in Section 10.1.4 with the
initial valid entries shown in Figure 6.
Reason for Need: Knowing the service provider's belief of mobility
may assist the PSAP with the handling of the call.
How Used by Call Taker: To determine whether to assume the location
of the caller might change.
+-----------+----------------------------+
| Token | Description |
+-----------+----------------------------+
| Mobile | The device is able to move |
| | at any time |
| Fixed | The device is not expected |
| | to move unless the |
| | service is relocated |
| Nomadic | The device is not expected |
| | to change its point of |
| | attachment while on a |
| | call |
| Unknown | No information is known |
| | about the service |
| | mobility environment for |
| | the device |
+-----------+----------------------------+
Figure 6: Service Environment Registry
4.2.4. EmergencyCallData.ServiceInfo Example
<?xml version="1.0" encoding="UTF-8"?>
<svc:EmergencyCallData.ServiceInfo
xmlns:svc="urn:ietf:params:xml:ns:EmergencyCallData:ServiceInfo">
<svc:DataProviderReference>2468.IBOC.MLTS.1359@example.org
</svc:DataProviderReference>
<svc:ServiceEnvironment>Business</svc:ServiceEnvironment>
<svc:ServiceType>MLTS-hosted</svc:ServiceType>
<svc:ServiceMobility>Fixed</svc:ServiceMobility>
</svc:EmergencyCallData.ServiceInfo>
Figure 7: EmergencyCallData.ServiceInfo Example.
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Internet-Draft Additional Call Data July 20154.3. Device Information
This block provides information about the device used to place the
call. It should be provided by any service provider that knows what
device is being used, and by the device itself. The mime subtype is
"application/EmergencyCallData.DeviceInfo+xml".
4.3.1. Device Classification
Data Element: Device Classification
Use: Optional
XML Element: <DeviceClassification>
Description: This data element defines the kind of device making the
emergency call. If the device provides the data structure, the
device information SHOULD be provided. If the service provider
provides the structure and it knows what the device is, the
service provider SHOULD provide the device information. Often the
carrier does not know what the device is. It is possible to
receive two Additional Data Associated with a Call data
structures, one created by the device and one created by the
service provider. This information describes the device, not how
it is being used. This data element defines the kind of device
making the emergency call. A registry is created in
Section 10.1.6 with the initial set of values as shown in
Figure 8.
Reason for Need: The device classification implies the capability of
the calling device and assists in identifying the meaning of the
emergency call location information that is being presented. For
example, does the device require human intervention to initiate a
call or is this call the result of programmed instructions? Does
the calling device have the ability to update location or
condition changes? Is this device interactive or a one-way
reporting device?
How Used by Call Taker: May provide the call taker context regarding
the caller, the capabilities of the calling device or the
environment in which the device is being used, and may assist in
understanding the location information and capabilities of the
calling device. For example, a cordless handset may be outside or
next door.
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Internet-Draft Additional Call Data July 20154.3.3. Device Model Number
Data Element: Device Model Number
Use: Optional
XML Element: <DeviceModelNr>
Description: Model number of the device.
Reason for Need: Used by PSAP management for after-action
investigation/resolution.
How Used by Call Taker: Probably not used by the calltaker, but by
PSAP management.
4.3.4. Unique Device Identifier
Data Element: Unique Device Identifier
Use: Optional
XML Element: <UniqueDeviceID>
XML Attribute: <TypeOfDeviceID>
Description: A string that identifies the specific device (or the
device's current SIM) making the call or creating an event. Note
that more than one <UniqueDeviceID> may be present, to supply more
than one of the identifying values.
The <TypeOfDeviceID> attribute identifies the type of device
identifier. A registry is created in Section 10.1.7 with an
initial set of values shown in Figure 9.
Reason for Need: Uniquely identifies the device (or, in the case of
IMSI, a SIM), independent of any signaling identifiers present in
the call signaling stream.
How Used by Call Taker: Probably not used by the call taker; may be
used by PSAP management during an investigation. (For example, if
a PSAP experiences repeated false/accidental calls and there is no
callback number or it isn't usable, the PSAP may need to try and
track down the device using various means (e.g., contacting
service providers in the area). In the case of handsets without
current service, it may be possible to determine who last had
service. Another example might be a disconnected call where the
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Internet-Draft Additional Call Data July 20154.3.6. Device/Service Specific Additional Data Structure Type
Data Element: Type of device/service-specific additional data
structure
Use: Conditional. MUST be provided when device/service specific-
additional URI is provided
XML Element: <DeviceSpecificType>
Description: A value from the registry defined in Section 10.1.8 to
describe the type of data located at the device/service-specific
additional data structure. The initial values shown in Figure 10
currently only include IEEE 1512, which is the USDoT model for
traffic incidents.
Reason for Need: This data element allows identification of
externally defined schemas, which may have additional data that
may assist in emergency response.
How Used by Call Taker: This data element allows the end user (call
taker or first responder) to know what type of additional data may
be available to aid in providing the needed emergency services.
Note: Information which is specific to a location or a caller
(person) should not be placed in this section.
+----------+----------------------------+--------------------------------+
| Token | Description | Specification |
+----------+----------------------------+--------------------------------+
| IEEE1512 | Common Incident Management |IEEE 1512-2006 |
| | Message Set (USDoT model |https://standards.ieee.org/ |
| | for traffic incidents) |findstds/standard/1512-2006.html|
+----------+----------------------------+--------------------------------+
Figure 10: Device/Service Data Type Registry
4.3.7. Issues with getting new types of data into use
This document describes two mechanisms that allow extension of the
kind of data provided with an emergency call: define a new block or
define a new service specific additional data URL for the DeviceInfo
block. While defining new data types and getting a new device or
application to send the new data may be easy, getting PSAPs and
responders to actually retrieve the data and use it will be
difficult. New mechanism providers should understand that acquiring
and using new forms of data usually require software upgrades at the
PSAP and/or responders, as well as training of call takers and
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responders in how to interpret and use the information. Legal and
operational review may also be needed. Overwhelming a call taker or
responder with too much information is highly discouraged. Thus, the
barrier to supporting new data is quite high.
The mechanisms this document describes are meant to encourage
development of widely supported, common data formats for classes of
devices. If all manufacturers of a class of device use the same
format, and the data can be shown to improve outcomes, then PSAPs and
responders may be encouraged to upgrade their systems and train their
staff to use the data. Variations, however well intentioned, are
unlikely to be supported.
Implementers should consider that data from sensor-based devices in
some cases may not be useful to call takers or PSAPs (and privacy,
liability, or other considerations might preclude the PSAP from
touching the data), but may be of use to responders. Each data item
provided with the call in conformance with this document can be
accessed by responders or other entities in the emergency services,
whether or not the data is accessed by the PSAP.
4.3.8. Choosing between defining a new type of block or new type of device/service specific additional data
For devices that have device or service specific data, there are two
choices to carry it. A new block can be defined, or the device/
service specific additional data URL the DeviceInfo block can be used
and a new type for it defined . The data passed would likely be the
same in both cases. Considerations for choosing which mechanism to
register under include:
Applicability: Information which will be carried by many kinds of
devices or services are more appropriately defined as separate
blocks.
Privacy: Information which may contain private data may be better
sent in the DeviceInfo block, rather than a new block so that
implementations are not tempted to send the data by value, and
thus having more exposure to the data than forcing the data to be
retrieved via the URL in DeviceInfo.
Size: Information which may be very large may be better sent in the
DeviceInfo block, rather than a new block so that implementations
are not tempted to send the data by value. Conversely, data which
is small may best be sent in a separate block so that it can be
sent by value
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Availability of a server: Providing the data via the device block
requires a server be made available to retrieve the data.
Providing the data via new block allows it to be sent by value
(CID).
4.3.9. EmergencyCallData.DeviceInfo Example
<?xml version="1.0" encoding="UTF-8"?>
<dev:EmergencyCallData.DeviceInfo
xmlns:dev="urn:ietf:params:xml:ns:EmergencyCallData:DeviceInfo">
<dev:DataProviderReference>d4b3072df.201409182208075@example.org
</dev:DataProviderReference>
<dev:DeviceClassification>fixed</dev:DeviceClassification>
<dev:DeviceMfgr>Nokia</dev:DeviceMfgr>
<dev:DeviceModelNr>Lumia 800</dev:DeviceModelNr>
<dev:UniqueDeviceID TypeOfDeviceID="IMEI">35788104
</dev:UniqueDeviceID>
</dev:EmergencyCallData.DeviceInfo>
Figure 11: EmergencyCallData.DeviceInfo Example.
4.4. Owner/Subscriber Information
This block describes the owner of the device (if provided by the
device) or the subscriber information (if provided by a service
provider). The contact location is not necessarily the location of
the caller or incident, but is rather the nominal contact address.
The MIME type is "application/EmergencyCallData.SubscriberInfo+xml".
In some jurisdictions some or all parts of the subscriber-specific
information are subject to privacy constraints. These constraints
vary but dictate which information can be displayed and logged. A
general privacy indicator expressing a desire for privacy by the
subscriber is provided. The interpretation of how this is applied is
left to the receiving jurisdiction as the custodians of the local
regulatory requirements. This matches an equivalent privacy flag
provided in some legacy emergency call systems.
4.4.1. Subscriber Data Privacy Indicator
Attribute: 'privacyRequested', Boolean.
Use: Conditional. This attribute MUST be provided if the owner/
subscriber information block is not empty.
Description: The subscriber data privacy indicator specifically
expresses the subscriber's desire for privacy. In some
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jurisdictions subscriber services can have a specific "Type of
Service" which prohibits information, such as the name of the
subscriber, from being displayed. This attribute is provided to
explicitly indicate whether the subscriber service includes such
constraints. The interpretation of this indicator is left to each
jurisdiction (in keeping with the semantics of the privacy
indicator provided in some legacy emergency call systems).
Because the interpretation of this indicator varies based on local
regulations, this document cannot describe the exact semantics nor
indicate which fields are affected (the application of this
indicator might affect the display of data contained in any of the
blocks).
Reason for Need: Some jurisdictions require subscriber privacy to be
observed when processing emergency calls.
How Used by Call Taker: Where privacy is indicated the call taker
may not have access to some aspects of the subscriber information.
4.4.2. xCard for Subscriber's Data
Data Element: xCARD for Subscriber's Data
Use: Conditional. Subscriber data MUST be provided unless it is not
available. Some services, such as prepaid phones, non-initialized
phones, etc., do not have information about the subscriber.
XML Element: <SubscriberData>
Description: Information known by the service provider or device
about the subscriber; e.g., Name, Address, Individual Telephone
Number, Main Telephone Number and any other data. <n>, <org> (if
appropriate), <adr>, <tel>, <email> are suggested at a minimum.
If more than one <tel> property is provided, a parameter from the
vCard Property Value registry MUST be specified on each <tel>.
While some data (such as <anniversary>) might not seem obviously
relevant for emergency services, any data is potentially useful in
some emergency circumstances.
Reason for Need: When the caller is unable to provide information,
this data may be used to obtain it
How Used by Call Taker: Obtaining critical information about the
caller and possibly the location when it is not able to be
obtained otherwise. While the location here is not necessarily
that of caller, in some circumstances it can be helpful in
locating the caller when other means have failed.
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This section defines how to convey additional data to an emergency
service provider. Two different means are specified: the first uses
the call signaling; the second uses the <provided-by> element of a
PIDF-LO [RFC4119].
1. First, the ability to embed a Uniform Resource Identifier (URI)
in an existing SIP header field, the Call-Info header, is
defined. The URI points to the additional data structure. The
Call-Info header is specified in Section 20.9 of [RFC3261]. This
document adds a new compound token starting with the value
'EmergencyCallData' for the Call-Info "purpose" parameter. If
the "purpose" parameter is set to a value starting with
'EmergencyCallData', then the Call-Info header contains either an
HTTPS URL pointing to an external resource or a CID (content
indirection) URI that allows the data structure to be placed in
the body of the SIP message. The "purpose" parameter also
indicates the kind of data (by its MIME subtype) that is
available at the URI. As the data is conveyed using a URI in the
SIP signaling, the data itself may reside on an external
resource, or may be contained within the body of the SIP message.
When the URI refers to data at an external resource, the data is
said to be passed by reference. When the URI refers to data
contained within the body of the SIP message, the data is said to
be passed by value. A PSAP or emergency responder is able to
examine the type of data provided and selectively inspect the
data it is interested in, while forwarding all of it (the values
or references) to downstream entities. To be conveyed in a SIP
body, additional data about a call is defined as a series of MIME
objects. Each block defined in this document is an XML data
structure identified by its MIME type. (Blocks defined by others
may be encoded in XML or not, as identified by their MIME
registration.) As usual, whenever more than one MIME part is
included in the body of a message, MIME multipart (i.e.,
'multipart/mixed') encloses them all. This document defines a
set of XML schemas and MIME types used for each block defined
here. When additional data is passed by value in the SIP
signaling, each CID URL points to one block in the body.
Multiple URIs are used within a Call-Info header field (or
multiple Call-Info header fields) to point to multiple blocks.
When additional data is provided by reference (in SIP signaling
or the <provided-by> element of a PIDF-LO), each HTTPS URL
references one block; the data is retrieved with an HTTPS GET
operation, which returns the block as an object (the blocks
defined here are returned as XML objects).
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2. Second, the ability to embed additional data structures in the
<provided-by> element of a PIDF-LO [RFC4119] is defined. In
addition to service providers in the call path, the access
network provider may also have similar information that can be
valuable to the PSAP. When the access network provider supplies
location information in the form of a PIDF-LO from a location
server via a location configuration protocol, it has the ability
to add the data structures defined in this document within the
PIDF-LO. The data in these data structures is not specific to
the location itself, but rather provides descriptive information
having to do with the immediate circumstances about the provision
of the location (e.g., the identity of the access network
provider, how to contact that entity, what kind of service the
access network provides, subscriber information, etc.). This
data is similar in nearly every respect to the data known by
service providers in the path of the call. When the access
network provider and service provider are separate entities, the
access network does not participate in the application layer
signaling (and hence cannot add a Call-Info header field to the
SIP message), but can provide location information in a PIDF-LO.
The <provided-by> element of the PIDF-LO is a mechanism for the
access network provider to supply the information. For this
reason, this document describes a namespace per [RFC4119] for
inclusion in the <provided-by> element of a PIDF-LO for adding
information known to the access network provider. The access
network provider SHOULD provide additional data within a
<provided-by> element of a PDIF-LO it returns for emergency use
(e.g., if requested with a HELD "responseTime" attribute of
"emergencyRouting" or "emergencyDispatch" [RFC5985]).
One or more blocks of data registered in the Emergency Call
Additional Data registry, as defined in Section 10.1.9, can be
included or referenced in the SIP signaling (using the Call-Info
header field) or in the <provided-by> element of a PIDF-LO. For
interoperability, only blocks in the registry are permitted to be
sent using the mechanisms specified in this document. Since multiple
entities are expected to provide sets of data, the data itself needs
information describing the source. Consequently, each entity adding
additional data MUST supply a "Data Provider" block. All other
blocks are optional, but each entity SHOULD supply all blocks where
it has at least some of the information in the block.
5.1. Transmitting Blocks using the Call-Info Header
A URI to a block MAY be inserted in any SIP request or response
method (most often INVITE or MESSAGE) with a Call-Info header field
containing a purpose value starting with 'EmergencyCallData', a dot
("."), and the type of data available at the URI. The type of data
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is denoted by including the root of the MIME subtype (the
'EmergencyCallData' prefix is not repeated), omitting any suffix such
as '+xml'). For example, when referencing a block with MIME type
'application/EmergencyCallData.ProviderInfo+xml', the 'purpose'
parameter is set to 'EmergencyCallData.ProviderInfo'. An example
"Call-Info" header field for this would be:
Call-Info: https://www.example.com/23sedde3;
purpose="EmergencyCallData.ProviderInfo"
A Call-info header with a purpose value starting with
'EmergencyCallData' only has meaning in the context of an emergency
call (as ascertained by the presence of an emergency service URN in a
Request-URI header of a SIP message), test emergency calls (using an
appropriate service URN), and some private-use calls where the
endpoints have a preexisting relationship and privacy concerns do not
apply because of the relationship; use in other contexts is undefined
and is likely to unnecessarily expose confidential data.
If the data is provided by reference, an HTTPS URI MUST be included
and consequently Transport Layer Security (TLS) protection is applied
for protecting the retrieval of the information.
The data may also be supplied by value in any SIP request or response
method that is permitted to contain a body (i.e., not a BYE request).
In this case, Content Indirection (CID) [RFC2392] is used, with the
CID URL referencing the MIME body part containing the data. Note
that [RFC3261] forbids proxies from altering message bodies, so
entities in the call path that add blocks by value need to do so
using an appropriate SIP entity (e.g., a back-to-back user agent).
Transmitting data by value is especially useful in certain cases,
such as when the data exists in or is generated by the originating
device, but is not intended for very large data blocks. Additional
security and privacy considerations apply to data transmitted by
value, as discussed in Section 8 and Section 9.
More than one Call-Info header with a purpose value starting with
'EmergencyCallData' can be expected, but at least one MUST be
provided. The device MUST provide one if it knows no service
provider is in the path of the call. The device MAY insert one if it
uses a service provider. Any service provider in the path of the
call MUST insert its own. For example, a device, a telematics
service provider in the call path, as well as the mobile carrier
handling the call will each provide one. There may be circumstances
where there is a service provider who is unaware that the call is an
emergency call and cannot reasonably be expected to determine that it
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is an emergency call. In that case, that service provider is not
expected to provide EmergencyCallData.
5.2. Transmitting Blocks by Reference using the <provided-by> Element
The <EmergencyCallDataReference> element is used to transmit an
additional data block by reference within a <provided-by> element of
a PIDF-LO. The <EmergencyCallDataReference> element has two
attributes: 'ref' to specify the URL, and 'purpose' to indicate the
type of data block referenced. The value of 'ref' is an HTTPS URL
that resolves to a data structure with information about the call.
The value of 'purpose' is the same as used in a 'Call-Info' header
field (as specified in Section 5.1).
For example, to reference a block with MIME type 'application/
EmergencyCallData.ProviderInfo+xml', the 'purpose' parameter is set
to 'EmergencyCallData.ProviderInfo'. An example
<EmergencyCallDataReference> element for this would be:
<EmergencyCallDataReference ref="https://www.example.com/23sedde3"
purpose="EmergencyCallData.ProviderInfo"/>
The <EmergencyCallDataReference> element transmits one data block;
multiple data blocks may be transmitted by using multiple
<EmergencyCallDataReference> elements. Multiple
<EmergencyCallDataReference> elements MAY be included as child
elements inside the <provided-by> element.
The following is a simplified example:
<provided-by
<EmergencyCallDataReference
purpose="EmergencyCallData.ServiceInfo"
ref="https://example.com/ref2" />
<EmergencyCallDataReference
purpose="EmergencyCallData.ProviderInfo"
ref="https://example.com/ref3" />
<EmergencyCallDataReference
purpose="EmergencyCallData.Comment"
ref="https://example.com/ref4" />
</provided-by>
Example <provided-by> by Reference
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For an example in context, Figure 18 shows a PIDF-LO example with an
<EmergencyCallDataReference> element pointing to an
EmergencyCallData.ServiceInfo data block with the URL in the 'ref'
attribute and the purpose attribute set to
"EmergencyCallData.ServiceInfo".
5.3. Transmitting Blocks by Value using the <provided-by> Element
It is RECOMMENDED that access networks supply the data specified in
this document by reference, but they MAY provide the data by value.
The <EmergencyCallDataValue> element is used to transmit one or more
additional data blocks by value within a <provided-by> element of a
PIDF-LO. Each block being transmitted is placed (as a child element)
inside the <EmergencyCallDataValue> element. (The same XML structure
as would be contained in the corresponding MIME type body part is
placed inside the <EmergencyCallDataValue> element.) Multiple
<EmergencyCallDataValue> elements MAY be included as child elements
in the <provided-by> element.
The following is a simplified example:
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today. For example, adding a PIDF-LO, SDP, and additional data in
body of a SIP message requires a 'multipart' message body.
RFC 3204 [RFC3204] and RFC 3459 [RFC3459] define the 'handling'
parameter for the Content-Disposition header field. These RFCs
describe how a UAS reacts if it receives a message body whose content
type or disposition type it does not understand. If the 'handling'
parameter has the value "optional", the UAS ignores the message body.
If the 'handling' parameter has the value "required", the UAS returns
a 415 (Unsupported Media Type) response. The 'by-reference'
disposition type allows a SIP message to contain a reference to the
body part, and the SIP UA processes the body part according to the
reference. This is the case for the Call-info header containing a
Content Indirection (CID) URL.
As an example, a SIP message indicates the Content-Disposition
parameter in the body of the SIP message as shown in Figure 14.
Content-Type: application/sdp
...Omit Content-Disposition here; defaults are ok
...SDP goes in here
--boundary1
Content-Type: application/pidf+xml
Content-ID: <target123@atlanta.example.com>
Content-Disposition: by-reference;handling=optional
...PIDF-LO goes in here
--boundary1--
Content-Type: application/EmergencyCallData.ProviderInfo+xml
Content-ID: <1234567890@atlanta.example.com>
Content-Disposition: by-reference; handling=optional
...Data provider information data goes in here
--boundary1--
Figure 14: Example for use of the Content-Disposition Parameter in
SIP
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<uri>geo:60.210796,24.812924</uri>
</geo>
<geo>
<parameters><type><text>home</text></type>
</parameters>
<uri>geo:39.746537,-75.548027</uri>
</geo>
<key>
<parameters>
<type><text>home</text></type>
</parameters>
<uri>https://www.example.com/key.asc
</uri>
</key>
<tz><text>Finland/Helsinki</text></tz>
<url>
<parameters><type><text>home</text></type>
</parameters>
<uri>http://example.com/hannes.tschofenig
</uri>
</url>
</vcard>
</pi:DataProviderContact>
</pi:EmergencyCallData.ProviderInfo>
--boundary1--
Figure 16: End Device sending SIP INVITE with Additional Data
In this example, information available to the access network provider
is included in the call setup message only indirectly via the use of
the location reference. The PSAP has to retrieve it via a separate
look-up step. Since the access network provider and the VoIP service
provider are two independent entities in this scenario, the access
network provider is not involved in application layer exchanges; the
SIP INVITE transits the access network transparently, as illustrated
in steps #1 and #2 (the access network does not alter the SIP
INVITE).
The VoIP service provider receives the message and determines, based
on the Service URN, that the incoming request is an emergency call.
It performs typical emergency services related tasks (such as
location-based routing), and adds additional data, namely service and
subscriber information as well as data provider information #2, to
the outgoing message. For the example we assume a VoIP service
provider that deploys a back-to-back user agent allowing additional
data to be included in the body of the SIP message (rather than by
reference), which allows us to illustrate the use of multiple data
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<xs:attribute name="ref" type="xs:anyURI"
use="required"/>
</xs:restriction>
</xs:complexContent>
</xs:complexType>
<!-- Additional Data By Value -->
<xs:complexType name="EmergencyCallDataValueType">
<xs:sequence>
<xs:element name="EmergencyCallData.ProviderInfo"
type="pi:ProviderInfoType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="EmergencyCallData.ServiceInfo"
type="svc:ServiceInfoType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="EmergencyCallData.DeviceInfo"
type="dev:DeviceInfoType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="EmergencyCallData.SubscriberInfo"
type="sub:SubscriberInfoType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="EmergencyCallData.Comment"
type="com:CommentType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:schema>
Figure 24: provided-by XML Schema
8. Security Considerations
The data structures described in this document contain information
usually considered private. When information is provided by value,
entities that are a party to the SIP signaling (such as proxy servers
and back-to-back user agents) will have access to it and need to
protect it against inappropriate disclosure. An entity that is able
to eavesdrop on the SIP signaling will also have access. Some access
types (such as in-the-clear Wi-Fi) are more vulnerable than others
(such as 3G or 4G cellular data traffic) to eavesdropping.
Mechanisms that protect against eavesdropping (such as Transport
Layer Security (TLS)) SHOULD be preferentially used whenever
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feasible. (This requirement is not a "MUST" because there is an
existing deployed base of clear-text SIP, and also because, as an
emergency call, it is more important for the call to go through than
for it to be protected; e.g., the call MUST proceed even if the TLS
negotiation or certificate verification fails for whatever reason.)
When information is provided by reference, HTTPS is REQUIRED for
dereferencing, and the provider of the information is REQUIRED to
validate the credentials of the requester. While the creation of a
public key infrastructure (PKI) that has global scope may be
difficult, the alternatives to creating devices and services that can
provide critical information securely are more daunting. The
provider of the information MAY enforce any policy it wishes to use,
but PSAPs and responder agencies SHOULD deploy a PKI so that
providers of additional data can check the certificate of the client
(the requester) and decide the appropriate policy to enforce based on
that certificate.
Ideally, the PSAP and emergency responders will be given credentials
signed by an authority trusted by the data provider. In most
circumstances, nationally recognized credentials are sufficient; the
emergency services community within a country can arrange a PKI, data
providers can be provisioned with the root CA public key for the
country. Some nations are developing a PKI for this, and related,
purposes. Since calls could be made from devices where the device
and/or the service provider(s) are not local to the emergency
services authorities, globally recognized credentials are useful.
This might be accomplished by extending the notion of the "forest
guide" described in [RFC5582] to allow the forest guide to provide
the credential of the PKI root for areas for which it has coverage
information, but standards for such a mechanism are not yet
available. In its absence, the data provider needs to obtain by out
of band means the root CA credentials for any areas to which it is
willing to provide additional data. With the credential of the root
CA for a national emergency services PKI, the data provider server
can validate the credentials of an entity requesting additional data
by reference.
The data provider also needs a credential that can be verified by the
emergency services to know that it is receiving data from an
authorized server. The emergency services authorities could provide
credentials, distinguishable from credentials provided to emergency
responders and PSAPs, which could be used to validate data providers.
Such credentials would have to be acceptable to any PSAP or responder
that could receive a call with additional data supplied by that
provider. This would be extensible to global credential validation
using the forest guide as mentioned above. In the absence of such
credentials, the emergency services authorities could maintain a list
of local data providers' credentials as provided to them out of band.
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At a minimum, the emergency services authorities could obtain a
credential from the DNS entry of the domain in the Additional Data
URI to at least validate that the server is known to the domain
providing the URI.
Data provided by devices by reference have similar credential
validation issues as for service providers, and while the solutions
are the same, the challenges of doing so for every device are
obviously more difficult, especially when considering root
certificate updates, revocation lists, etc. However, in general,
devices are not expected to provide data directly by reference, but
rather, to either provide data by value, or upload the data to a
server which can more reliably make it available and more easily
enforce security policy. Devices which do provide data directly by
reference, which might include fixed-location sensors, will need to
be capable of handling this.
Much of the information supplied by service providers and devices is
private and confidential; service providers and devices generally go
to lengths to protect this information; disclosing it in the context
of an emergency call is a trade-off to protect the greater interest
of the customer in an emergency.
Neither service providers nor devices will supply private information
unless the call is recognized as an emergency call. In cellular
telephony systems (such as those using 3GPP IMS), there are different
procedures for an originating device to place an emergency versus a
normal call. If a call that is really an emergency call is initiated
as a normal call and the cellular service provider recognizes this,
3GPP IMS permits the service provider to either accept the call
anyway or reject it with a specific code that instructs the device to
retry the call as an emergency call. Service providers ought to
choose the latter, because otherwise the device will not have
included the information specified in this document (since the device
didn't recognize the call as being an emergency call).
9. Privacy Considerations
This document enables functionality for conveying additional
information about the caller and the caller's device and service to
the callee. Some of this information is personal data and therefore
privacy concerns arise. An explicit privacy indicator for
information directly relating to the caller's identity is defined and
use is mandatory. However, observance of this request for privacy
and which information it relates to is determined by the destination
jurisdiction (which replicates functionality provided in some legacy
emergency services systems).
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There are a number of privacy concerns with non-emergency real-time
communication services that are also applicable to emergency calling.
Data protection regulation world-wide has, however, decided to create
exceptions for emergency services since the drawbacks of disclosing
personal data are outweighed by the benefit for the emergency caller.
Hence, the data protection rights of individuals are commonly waived
for emergency situations. There are, however, still various
countries that offer some degree of anonymity for the caller towards
PSAP call takers.
The functionality defined in this document far exceeds the amount of
information sharing available in the legacy POTS system. For this
reason there are additional privacy threats to consider, which are
described in more detail in [RFC6973].
Stored Data Compromise: There is an increased risk of stored data
compromise since additional data is collected and stored in
databases. Without adequate measures to secure stored data from
unauthorized or inappropriate access at access network providers,
service providers, end devices, as well as PSAPs, individuals are
exposed to potential financial, reputational, or physical harm.
Misattribution: If the personal data collected and conveyed is
incorrect or inaccurate then this may lead to misattribution.
Misattribution occurs when data or communications related to one
individual are attributed to another.
Identification: By the nature of the additional data and its
capability to provide much richer information about the caller,
the call, and the location, the calling party is identified in a
much better way. Some users may feel uncomfortable with this
degree of information sharing even in emergency services
situations.
Secondary Use: There is a risk of secondary use, which is the use of
collected information about an individual without the individual's
consent for a purpose different from that for which the
information was collected. The stated purpose of the additional
data is for emergency services purposes but theoretically the same
information could be used for any other call as well.
Additionally, parties involved in the emergency call may retain
the obtained information and may re-use it for other, non-
emergency services purposes.
Disclosure: When the data defined in this document is not properly
protected (while in transit with traditional communication
security techniques, and while stored using access control
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mechanisms) there is the risk of disclosure, which is the
revelation of private information about an individual.
To mitigate these privacy risks the following countermeasures can be
taken:
In regions where callers can elect to suppress certain personally
identifying information, network or PSAP functionality can inspect
privacy flags within the SIP headers to determine what information
may be passed, stored, or displayed to comply with local policy or
law. RFC 3325 [RFC3325] defines the "id" priv-value token. The
presence of this privacy type in a Privacy header field indicates
that the user would like the network asserted identity to be kept
private with respect to SIP entities outside the trust domain with
which the user authenticated, including the PSAP.
This document defines various data structures that contain privacy-
sensitive data. For example, identifiers for the device (e.g.,
serial number, MAC address) or account/SIM (e.g., IMSI), contact
information for the user, location of the caller. Local regulations
may govern which data is provided in emergency calls, but in general,
the emergency call system is aided by the information described in
this document. There is a tradeoff between the privacy
considerations and the utility of the data. For protection, this
specification requires all retrieval of data passed by reference to
be protected against eavesdropping and alteration via communication
security techniques (namely TLS). Furthermore, security safeguards
are required to prevent unauthorized access to stored data. Various
security incidents over at least the past few decades have shown that
data breaches are not uncommon and are often caused by lack of proper
access control frameworks, software bugs (such as buffer overflows),
or missing input parsing (such as SQL injection attacks). The risks
of data breaches is increased with the obligation for emergency
services to retain emergency call related data for extended periods
(e.g., several years are the norm).
Finally, it is also worth highlighting the nature of the SIP
communication architecture, which introduces additional complications
for privacy. Some forms of data can be sent by value in the SIP
signaling or by reference (a URL in the SIP signaling). When data is
sent by value, all intermediaries have access to the data. As such,
these intermediaries may also introduce additional privacy risk.
Therefore, in situations where the conveyed information is privacy-
sensitive and intermediaries are involved, transmitting by reference
might be appropriate, assuming the source of the data can operate a
sufficient dereferencing infrastructure and that proper access
control policies are available for distinguishing the different
entities dereferencing the reference. Without access control
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policies any party in possession of the reference is able to resolve
the reference and to obtain the data, including intermediaries.
10. IANA Considerations10.1. Registry creation
This document creates a new registry called 'Emergency Call
Additional Data'. The following sub-registries are created for this
registry.
10.1.1. Provider ID Series Registry
This document creates a new sub-registry called "Additional Call Data
Provider ID Series". As defined in [RFC5226], this registry operates
under "Expert Review" rules. The expert should determine that the
entity requesting a new value is a legitimate issuer of service
provider IDs suitable for use in Additional Call Data.
Private entities issuing or using internally-generated IDs are
encouraged to register here and to ensure that all IDs they issue or
use are unique. This guarantees that IDs issued or used by the
entity are globally unique and distinguishable from other IDs issued
or used by the same or a different entity. (Some organizations, such
as NENA, issue IDs that are unique among all IDs they issue, so an
entity using a combination of its NENA ID and the fact that it is
from NENA is globally unique. Other entities might not have an ID
issued by an organization such as NENA, so they are permitted to use
their domain name, but if so, it needs to be unique.)
The content of this registry includes:
Name: An identifier to be used in the 'ProviderIDSeries' element.
Source: The full name of the organization issuing the identifiers.
URL: A URL to the organization for further information.
The initial set of values is listed in Figure 1.
10.1.2. Service Environment Registry
This document creates a new sub-registry called 'Additional Call
Service Environment'. As defined in [RFC5226], this registry
operates under "Expert Review" rules. The expert should determine
that the entity requesting a new value is relevant for this service
element, and that the new value is distinct from existing values, and
its use is unambiguous.
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The content of this registry includes:
Token: The value to be used in the <ServiceEnvironment> element.
Description: A short description of the value.
The initial set of values is listed in Figure 4.
10.1.3. Service Type Registry
This document creates a new sub-registry called 'Additional Call
Service Type'. As defined in [RFC5226], this registry operates under
"Expert Review" rules. The expert should determine that the entity
requesting a new value is relevant for this service element and that
the requested value is clearly distinct from other values so that
there is no ambiguity as to when the value is to be used or which
value is to be used.
The content of this registry includes:
Name: The value to be used in the <ServiceType> element.
Description: A short description of the value.
The initial set of values is listed in Figure 5.
10.1.4. Service Mobility Registry
This document creates a new sub-registry called 'Additional Call
Service Mobility'. As defined in [RFC5226], this registry operates
under "Expert Review" rules. The expert should determine that the
entity requesting a new value is relevant for this service element
and that the requested value is clearly distinct from other values so
that there is no ambiguity as to when the value is to be used or
which value is to be used.
The content of this registry includes:
Token: The value used in the <ServiceMobility> element.
Description: A short description of the value.
The initial set of values is listed in Figure 6.
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This document creates a new sub-registry called 'Service Provider
Type'. As defined in [RFC5226], this registry operates under "Expert
Review". The expert should determine that the proposed new value is
distinct from existing values and appropriate for use in the
<TypeOfServicerProvider> element
The content of this registry includes:
Token: The value used in the <TypeOfProvider> element.
Description: A short description of the type of service provider.
The initial set of values is defined in Figure 2.
10.1.6. Device Classification Registry
This document creates a new sub-registry called 'Device
Classification'. As defined in [RFC5226], this registry operates
under "Expert Review" rules. The expert should consider whether the
proposed class is unique from existing classes and the definition of
the class will be clear to implementors and PSAPs/responders.
The content of this registry includes:
Token: Value used in the <DeviceClassification> element.
Description: Short description identifying the device type.
The initial set of values are defined in Figure 8.
10.1.7. Device ID Type Type Registry
This document creates a new sub-registry called 'Additional Call Data
Device ID Type'. As defined in [RFC5226], this registry operates
under "Expert Review" rules. The expert should ascertain that the
proposed type is well understood, and provides information which
PSAPs and responders are able to use to uniquely identify a device.
(For example, a biometric fingerprint used to authenticate a device
would not normally be useful by a PSAP or responder to identify a
device.)
The content of this registry includes:
Token: The value to be placed in the <TypeOfDeviceID> element.
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Description: Short description identifying the type of the device
ID.
The initial set of values are defined in Figure 9.
10.1.8. Device/Service Data Type Registry
This document creates a new sub-registry called 'Device/Service Data
Type Registry'. As defined in [RFC5226], this registry operates
under "Specification Required" rules, which include an explicit
expert review. The designated expert should ascertain that the
proposed type is well understood, and provides information useful to
PSAPs and responders. The specification must contain a complete
description of the data, and a precise format specification suitable
to allow interoperable implementations.
The content of this registry includes:
Token: The value to be placed in the <DeviceSpecificType> element.
Description: Short description identifying the data.
Specification: Citation for the specification of the data.
The initial set of values are listed in Figure 10.
10.1.9. Emergency Call Data Types Registry
This document creates a new sub-registry called 'Emergency Call Data
Types' in the 'purpose' registry established by RFC 3261 [RFC3261].
As defined in [RFC5226], this registry operates under "Specification
Required" rules, which include an explicit expert review. The expert
is responsible for verifying that the document contains a complete
and clear specification and the proposed functionality does not
obviously duplicate existing functionality. The expert is also
responsible for verifying that the block is correctly categorized per
the description of the categories in Section 1.
The registry contains an entry for every data block that can be sent
with an emergency call using the mechanisms as specified in this
document. Each data block is identified by the "root" of its MIME
subtype (which is the part after 'EmergencyCallData.'). If the MIME
subtype does not start with 'EmergencyCallData.', then it cannot be
registered here nor used in a Call-Info header as specified in this
document. The subtype MAY exist under any MIME media type (although
most commonly these are under 'Application/' this is NOT REQUIRED),
however, to be added to the registry the "root" needs to be unique
regardless of the MIME media type.
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The content of this registry includes:
Token: The root of the data's MIME subtype (not including the
'EmergencyCallData' prefix and any suffix such as '+xml')
Data About: A hint as to if the block is considered descriptive of
the call, the caller, or the location (or is applicable to more
than one), which may help PSAPs and other entities determine if
they wish to process the block. Note that this is only a hint;
entities need to consider the block's contents, not just this
field, when determining if they wish to process the block (which
is why the field only exists in the registry, and is not contained
within the block). The value MUST be either "The Call", "The
Caller", "The Location", or "Multiple". New values are created by
extending this registry in a subsequent RFC.
Reference: The document that describes the data object
Note that the tokens in this registry are part of the
'EmergencyCallData' compound value; when used as a value of the
'purpose' parameter of the Call-Info header, the values listed in
this registry are prefixed by 'EmergencyCallData.' per the
'EmergencyCallData' registation Section 10.2.
The initial set of values are listed in Figure 25.
+----------------+--------------+------------+
| Token | Data About | Reference |
+----------------+--------------+------------+
| ProviderInfo | The Call | [This RFC] |
| ServiceInfo | The Call | [This RFC] |
| DeviceInfo | The Call | [This RFC] |
| SubscriberInfo | The Call | [This RFC] |
| Comment | The Call | [This RFC] |
+----------------+--------------+------------+
Figure 25: Additional Data Blocks Registry
10.2. 'EmergencyCallData' Purpose Parameter Value
This document defines the 'EmergencyCallData' value for the "purpose"
parameter of the Call-Info header field. The Call-Info header and
the corresponding registry for the 'purpose' parameter was
established with RFC 3261 [RFC3261]. Note that 'EmergencyCallData'
is a compound value; when used as a value of the 'purpose' parameter
of the Call-Info header, 'EmergencyCallData' is immediately followed
by a dot ('.') and a value from the 'Emergency Call Data Types'
registry Section 10.1.9.
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Header Parameter New
Field Name Value Reference
---------- --------- ----------------- ---------
Call-Info purpose EmergencyCallData [This RFC]
10.3. URN Sub-Namespace Registration for <provided-by> Registry Entry
This section registers the namespace specified in Section 10.5.1 in
the provided-by registry established by RFC 4119, for usage within
the <provided-by> element of a PIDF-LO.
The schema for the <provided-by> element used by this document is
specified in Section 7.6.
10.4. MIME Registrations10.4.1. MIME Content-type Registration for 'application/ EmergencyCallData.ProviderInfo+xml'
This specification requests the registration of a new MIME type
according to the procedures of RFC 6838 [RFC6838] and guidelines in
RFC 7303 [RFC7303].
MIME media type name: application
MIME subtype name: EmergencyCallData.ProviderInfo+xml
Mandatory parameters: none
Optional parameters: charset (indicates the character encoding of
the contents)
Encoding considerations: Uses XML, which can contain 8-bit
characters, depending on the character encoding. See Section 3.2
of RFC 7303 [RFC7303].
Security considerations: This content type is designed to carry
the data provider information, which is a sub-category of
additional data about an emergency call. Since this data may
contain personal information, appropriate precautions might be
needed to limit unauthorized access, inappropriate disclosure, and
eavesdropping of personal information. Please refer to Section 8
and Section 9 for more information.
Interoperability considerations: None
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Published specification: [TBD: This specification]
Applications which use this media type: Emergency Services
Additional information:
Magic Number: None
File Extension: .xml
Macintosh file type code: 'TEXT'
Person and email address for further information: Hannes
Tschofenig, Hannes.Tschofenig@gmx.net
Intended usage: LIMITED USE
Author: This specification is a work item of the IETF ECRIT
working group, with mailing list address <ecrit@ietf.org>.
Change controller: The IESG <ietf@ietf.org>
10.4.2. MIME Content-type Registration for 'application/ EmergencyCallData.ServiceInfo+xml'
This specification requests the registration of a new MIME type
according to the procedures of RFC 6838 [RFC6838] and guidelines in
RFC 7303 [RFC7303].
MIME media type name: application
MIME subtype name: EmergencyCallData.ServiceInfo+xml
Mandatory parameters: none
Optional parameters: charset (indicates the character encoding of
the contents)
Encoding considerations: Uses XML, which can contain 8-bit
characters, depending on the character encoding. See Section 3.2
of RFC 7303 [RFC7303].
Security considerations: This content type is designed to carry
the service information, which is a sub-category of additional
data about an emergency call. Since this data may contain
personal information, appropriate precautions may be needed to
limit unauthorized access, inappropriate disclosure, and
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Security considerations: This content type is designed to carry
device information, which is a sub-category of additional data
about an emergency call. Since this data contains personal
information, appropriate precautions need to be taken to limit
unauthorized access, inappropriate disclosure to third parties,
and eavesdropping of this information. Please refer to Section 8
and Section 9 for more information.
Interoperability considerations: None
Published specification: [TBD: This specification]
Applications which use this media type: Emergency Services
Additional information:
Magic Number: None
File Extension: .xml
Macintosh file type code: 'TEXT'
Person and email address for further information: Hannes
Tschofenig, Hannes.Tschofenig@gmx.net
Intended usage: LIMITED USE
Author: This specification is a work item of the IETF ECRIT
working group, with mailing list address <ecrit@ietf.org>.
Change controller: The IESG <ietf@ietf.org>
10.4.4. MIME Content-type Registration for 'application/ EmergencyCallData.SubscriberInfo+xml'
This specification requests the registration of a new MIME type
according to the procedures of RFC 6838 [RFC6838] and guidelines in
RFC 7303 [RFC7303].
MIME media type name: application
MIME subtype name: EmergencyCallData.SubscriberInfo+xml
Mandatory parameters: none
Optional parameters: charset (indicates the character encoding of
the contents)
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Encoding considerations: Uses XML, which can contain 8-bit
characters, depending on the character encoding. See Section 3.2
of RFC 7303 [RFC7303].
Security considerations: This content type is designed to carry
owner/subscriber information, which is a sub-category of
additional data about an emergency call. Since this data contains
personal information, appropriate precautions need to be taken to
limit unauthorized access, inappropriate disclosure to third
parties, and eavesdropping of this information. Please refer to
Section 8 and Section 9 for more information.
Interoperability considerations: None
Published specification: [TBD: This specification]
Applications which use this media type: Emergency Services
Additional information:
Magic Number: None
File Extension: .xml
Macintosh file type code: 'TEXT'
Person and email address for further information: Hannes
Tschofenig, Hannes.Tschofenig@gmx.net
Intended usage: LIMITED USE
Author: This specification is a work item of the IETF ECRIT
working group, with mailing list address <ecrit@ietf.org>.
Change controller: The IESG <ietf@ietf.org>
10.4.5. MIME Content-type Registration for 'application/ EmergencyCallData.Comment+xml'
This specification requests the registration of a new MIME type
according to the procedures of RFC 6838 [RFC6838] and guidelines in
RFC 7303 [RFC7303].
MIME media type name: application
MIME subtype name: EmergencyCallData.Comment+xml
Mandatory parameters: none
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Optional parameters: charset (indicates the character encoding of
the contents)
Encoding considerations: Uses XML, which can contain 8-bit
characters, depending on the character encoding. See Section 3.2
of RFC 7303 [RFC7303].
Security considerations: This content type is designed to carry a
comment, which is a sub-category of additional data about an
emergency call. This data may contain personal information.
Appropriate precautions may be needed to limit unauthorized
access, inappropriate disclosure to third parties, and
eavesdropping of this information. Please refer to Section 8 and
Section 9 for more information.
Interoperability considerations: None
Published specification: [TBD: This specification]
Applications which use this media type: Emergency Services
Additional information:
Magic Number: None
File Extension: .xml
Macintosh file type code: 'TEXT'
Person and email address for further information: Hannes
Tschofenig, Hannes.Tschofenig@gmx.net
Intended usage: LIMITED USE
Author: This specification is a work item of the IETF ECRIT
working group, with mailing list address <ecrit@ietf.org>.
Change controller: The IESG <ietf@ietf.org>
10.5. URN Sub-Namespace Registration10.5.1. Registration for urn:ietf:params:xml:ns:EmergencyCallData
This section registers a new XML namespace, as per the guidelines in
RFC 3688 [RFC3688].
URI: urn:ietf:params:xml:ns:EmergencyCallData
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Registrant Contact: IETF, ECRIT Working Group (ecrit@ietf.org), as
delegated by the IESG (iesg@ietf.org).
XML: The XML schema can be found in Section 7.4.
URI: urn:ietf:params:xml:schema:emergencycalldata:comment
Registrant Contact: IETF, ECRIT Working Group (ecrit@ietf.org), as
delegated by the IESG (iesg@ietf.org).
XML: The XML schema can be found in Section 7.5.
10.7. VCard Parameter Value Registration
This document registers a new value in the vCARD Parameter Values
registry as defined by [RFC6350] with the following template:
Value: main
Purpose: The main telephone number, typically of an enterprise, as
opposed to a direct dial number of an individual employee
Conformance: This value can be used with the "TYPE" parameter
applied on the "TEL" property.
Example(s): TEL;VALUE=uri;TYPE="main,voice";PREF=1:tel:+1-418-656-90
00
11. Acknowledgments
This work was originally started in NENA and has benefitted from a
large number of participants in NENA standardization efforts,
originally in the Long Term Definition Working Group, the Data
Technical Committee and most recently the Additional Data working
group. The authors are grateful for the initial work and extended
comments provided by many NENA participants, including Delaine
Arnold, Marc Berryman, Guy Caron, Mark Fletcher, Brian Dupras, James
Leyerle, Kathy McMahon, Christian, Militeau, Ira Pyles, Matt Serra,
and Robert (Bob) Sherry. Amursana Khiyod, Robert Sherry, Frank
Rahoi, Scott Ross, and Tom Klepetka provided valuable feedback
regarding the vCard/xCard use in this specification.
We would also like to thank Paul Kyzivat, Gunnar Hellstrom, Martin
Thomson, Keith Drage, Laura Liess, Chris Santer, Barbara Stark, Chris
Santer, and Archie Cobbs for their review comments. Alissa Cooper
and Guy Caron deserves special mention for their detailed and
extensive review comments, which were very helpful and appreciated.
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</xs:restriction>
</xs:complexContent>
</xs:complexType>
<xs:element name="vcard" type="ns1:vcardType"/>
<xs:element name="group">
<xs:complexType>
<xs:group minOccurs="0" maxOccurs="unbounded"
ref="ns1:property"/>
<xs:attribute name="name" use="required"/>
</xs:complexType>
</xs:element>
</xs:schema>
Appendix B. XML Validation
This document defines a number of XML schemas and contains various
examples. Extracting the XML and validating the examples against the
schemas can be challenging, especially due to the formatting
limitations introduced by IETF RFCs. For those readers who copy the
XML schemas and examples directly from this document, please consider
that errors might be introduced due to line breaks and extra
whitespaces in the regular expressions contained in the vcard schema
in Appendix A. To validate the PIDF-LO from Figure 18 it is also
necessary to consult the referenced RFCs and copy the schemas
necessary for successful validation.
The XML schemas found in this document include a 'SchemaLocation'
attribute. Depending on the location of the downloaded schema files
you may need to adjust this schema location or configure your XML
editor to point to the location.
For convenience of readers, the schemas are available at http://ip-emergency.net/additional-data.zip and the XML examples are available
at the IETF ECRIT Working Group wiki page [ECRIT-WG-wiki].
Note to RFC Editor: After IANA has published the schemas, the above
link to the schemas should be replaced with [IANA-XML-Schemas].
Authors' Addresses
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